As we interact with our environment, we perform dextrous, coordinated movements of multiple effectors. I am particularly interested in eye/hand coordination - the processes by which we use vision to guide our arm and hand movements. We study the premotor cortex in Rhesus monkeys trained to perform visuomotor behaviors. Neurons in premotor cortex are active in relation to reaching, and some of them project polysynaptically to the eye muscles, which implicates them in eye/hand coordination. The two overarching goals of this research are complementary: First, we will study the conditions under which sensory-motor transformations can be modified. Our pilot data suggest that training experience and the immediate demands of behavior can shape neural response properties, causing premotor neurons to become more sensitive to the position of the eyes. Inducing a sensitivity to a new sensory modality is an extreme form of neural plasticity, of a type typically only seen after brain injury. The second goal of this research is to explore the role of the premotor cortex in behavior. Our pilot data indicate that premotor cortex may be even more versatile and flexible than is typically assumed. The chief significance of this research is that it will change our understanding of sensory-motor processing by showing it is more flexible and malleable than has been presumed. The chief innovation is in our use of multielectrode array recordings to perform longitudinal studies of learning in multiple brain areas simultaneously. Our main approach is to record high-volume neural data sets from multiple cortical areas while monkeys learn and perform motor behaviors. This will provide a rich and high-impact data set that will yield detailed comparative information about the premotor cortices. PUBLIC HEALTH RELEVANCE: Millions of Americans live with debilitating motor disorders, such as spinal cord injury, limb amputation, multiple sclerosis, and amyotrophic lateral sclerosis. Often, central nervous system function is intact, but peripheral damage prevents the translation of intentions into actions. Neural prostheses can assist immobilized individuals by extracting movement control signals directly from the cerebral cortex. This research will help us design prostheses that generalize to new contexts better than existing technologies can. Our work also has relevance for stroke recovery, since we have discovered a novel form of adaptability in motor control circuits.